<form id='myupload' action='/upload' method='post' enctype='multipart/form-data'>
  <div class="demo">
    <div class="btn">
      <span>添加附件</span>
      <input id="fileupload" type="file" name="file"></div>
    <div class="progress">
      <span class="bar"></span>
      <span class="percent">0%</span></div>
    <!-- 显示已上传的文件名 -->
    <div class="files"></div>
    <!-- 显示已上传的图片-->
    <div class="showimg"></div>
  </div>
  <input type="submit" onclick="gosubmit2()" /></form>
<script src="https://cdn.bootcss.com/jquery/1.6.4/jquery.js"></script>
<script type="text/javascript" src="https://cdn.bootcss.com/jquery.form/4.1.0/jquery.form.min.js"></script>
<script type="text/javascript">var bar = $('.bar'); //进度条
  var percent = $('.percent'); //获取上传百分比
  var showimg = $('.showimg'); //显示图片的div
  var progress = $('.progress'); //显示进度的div
  var files = $('.files'); //文件上传控件的input元素
  var btn = $('.btn span'); //按钮文本
  function gosubmit2() {
    $("#myupload").ajaxSubmit({
      dataType: 'json',
      //返回数据类型
      beforeSend: function() {
        showimg.empty();
        progress.show();
        var percentVal = '0%';
        bar.width(percentVal);
        percent.html(percentVal);
        btn.html('上传中..');
      },
      //更新进度条事件处理代码
      uploadProgress: function(event, position, total, percentComplete) {
        var percentVal = percentComplete + '%';
        bar.width(percentVal);
        percent.html(percentVal);
      },
      success: function(data) { //图片上传成功时
        //获取服务器端返回的文件数据
        alert(data.name + "," + data.pic + "," + data.size);
      },
      error: function(xhr) {
        btn.html(上传失败);
        bar.width('0');
        files.html(xhr.responseText);
      }
    });
  }</script>